FRESNO, Calif. — Environmental groups filed a lawsuit on Tuesday against the California Department of Public Health for failing to establish a safe drinking water standard for the cancer-causing chemical made famous in the film "Erin Brockovich."

The Natural Resources Defense Council and the Environmental Working Group claim the department is eight years late in setting the hexavalent chromium standard and has made no progress toward the goal.

The lawsuit claims the delay is unjustified and seeks a court order setting a faster timeline.

Studies show that hexavalent chromium, also known as chromium-6, can cause cancer in people and has been found to cause damage to the gastrointestinal tract, lymph nodes and liver of animals.

The chemical comes chiefly from industrial pollution – it's used for production of stainless steel, textile dyes, wood preservation, leather tanning and as an anti-corrosive – but also occurs naturally.

The dangers of chromium-6 became widely known after the film "Erin Brockovich" exposed the case of Pacific Gas & Electric Corp. The utility was accused of leaking the contaminant into the groundwater of Hinckley, a small desert town, causing health problems including cancer.

A year later in 2001, the California legislature directed public health agencies to set an enforceable drinking water standard for the chemical by 2004.

The process was delayed due to a scientific dispute over whether chromium-6 is carcinogenic when ingested in water, said Sam Delson, deputy director for external and legislative affairs at the California Environmental Protection Agency. It has long been established that chromium-6 is carcinogenic when inhaled.

Federal scientists at the National Toxicology Program confirmed in 2007 that it's also carcinogenic when ingested.

The California EPA then set a "public health goal" – a preliminary benchmark in creating a drinking water standard – for hexavalent chromium. But in 2010, the agency recommended stricter limits after research showed that fetuses, infants and children are more susceptible than adults to the cancer-causing effects of the chemical. That goal was set last year at .02 parts of hexavalent chromium per billion parts of water.

Results of state water quality testing conducted between 2000 and 2011 throughout California showed that about a third of the 7,000 drinking water sources tested had chromium-6 levels at or above that limit.

The highest concentrations were reported in southern California, including in Los Angeles, San Bernardino, and Santa Barbara counties.

Using the benchmark, the Department of Public Health must develop the standard as close as possible to the health goal, factoring in the technical feasibility and costs of water testing and treatment.

Department of Public Health spokesman Ken August said there is no typical timeline for how long it takes to develop a standard. The agency is currently preparing a cost-benefit analysis, he said, and will take another two to three years to establish the standard.

There is no federal standard for chromium-6. Last year, the U.S. EPA released recommendations for enhanced monitoring of the chemical in public water systems and is conducting a review of chromium-6 to decide whether to set a nationwide standard.